Personal computers are available in many different brands, sizes and types. The first generations of personal computers had limited processing power and graphic display capabilities. A keyboard was typically the only type of computer accessory used as user input device for those early personal computers. The keyboard is still a dominating user input device for personal computers because of its feasibility for massive input of text. In addition, with the advent of graphical user interfaces (GUI), pointing devices have become and remain a very common type of computer accessory. Within the context of the present patent application, a pointing device is a computer accessory adapted for allowing a computer user to control the position of a cursor in a graphical user interface of a computer, as well as to perform relation actions such as selection of an object presented in the graphical user interface. The computer mouse is probably the most known example of such a pointing device. Other known examples include a trackball, a joystick, and a touchpad.
From the many years that computer mice have been in widespread use it has become apparent that the usage is associated with various drawbacks. Several of those drawbacks relate to user ergonomics. One example of an ergonomic drawback of heavy usage of a computer mouse is neck, shoulder or elbow pain caused by asymmetric computer mouse reaching with one side of the body but not the other. The root of this problem is that the computer mouse is designed to be located and operated laterally either to the right or to the left of the keyboard.
Other frequent ergonomic problems that appear among many computer mouse users are repetitive strain injuries, such as carpal tunnel syndrome or tendonitis. These problems are believed to be caused by the gripping of the hand and flexing of the fingers upon the computer mouse.
Ergonomic pointing devices have therefore been developed as replacement of conventional computer mice. The assignee of this patent application, Contour Design, Inc., has taken the leadership in the development of ergonomic pointing devices which have been successfully sold for a number of years under the trademark RollerMouse®. PCT publication WO 02/043046 presents some earlier versions of RollerMouse® pointing devices.
The basic design of RollerMouse® pointing devices includes a housing which is designed to be placed adjacently to the lower lateral edge of the keyboard on a desktop surface or similar. (For a common QWERTY-type keyboard, the lower later edge is the edge just below the row of keys that includes the elongate space bar). An elongate cursor navigation member referred to as a rollerbar is accessible to the user at an upper part of the housing. The rollerbar is movably arranged on an elongate support member to allow rotation and translation of the rollerbar.
By rotating the rollerbar around its central axis and translation (sliding) it along the central axis, the user of a RollerMouse® pointing device may control the x and y coordinates of the cursor location in a graphical user interface of a computer to which the RollerMouse® pointing device is connected. Thus, the rollerbar acts as a cursor navigation member. To this end, the RollerMouse® pointing device has one or more built-in optical sensors capable of detecting the rotation and translation of the rollerbar, and controller means in the form of electronic circuitry capable of causing transmission of data regarding the detected rollerbar movement as cursor control signals to the computer. Furthermore, the rollerbar is designed to be depressible by the user, thereby allowing the user to perform actions corresponding to conventional mouse clicks. In addition to the rollerbar, the housing of the RollerMouse® pointing device has a set of buttons representing common mouse-related actions, such as left-click, right-click, double-click, etc.
As a result, the user may ergonomically operate the RollerMouse® pointing device to get full access to all mouse-related actions with only small hand and finger movements, using the right or left hand, or both hands, at the user's discretion. At the same time, since the RollerMouse® pointing device is located immediately below the keyboard, the user will be able to reach the keys of the keyboard with only minimum hand movements between the RollerMouse® pointing device and the keyboard. All in all, RollerMouse® pointing devices have proven effective in reducing ergonomic problems normally associated with computer cursor control.
PCT publication WO 2011/070522 presents some refined versions of RollerMouse® pointing devices. A major design leap was taken by the incorporation of the optical sensor on the inside of the rollerbar, in contrast to earlier designs in the field, where the optical sensor monitored the surface of the rollerbar from the outside.
The present inventors have realized that there is still room for certain improvements of pointing devices like, for instance, the ones referred to above. An objective of the present disclosure is therefore to provide one or more further improvements of the inner-sensor-based design concept disclosed in WO 2011/070522, the contents of which are hereby incorporated by reference in its entirety. However, it is to be noticed that the inventive improvements may at least to some extent be applied also to other pointing devices than the ones described in WO 2011/070522, including conventional, external-sensor designs.
One area for which the present inventors have identified a need for improvement is the arrangement for detecting clicks by depressing the rollerbar. Prior art pointing devices typically use a mechanical click switch beneath a part of the rollerbar or another element which moves together with the rollerbar when being depressed. When the rollerbar has been sufficiently depressed, the mechanical switch will be actuated. The rollerbar is conventionally supported by a resilient mechanism, such as one or more springs, acting as a counterforce to balance the downward pressure on the rollerbar when depressed and yielding a suitable resistance which prevents accidental depressions of the rollerbar and yet make the intended depression controllable for the user without requiring excessive click force.
A mechanical click switch and a resilient counterforce mechanism will be exposed to mechanical wear and be susceptible of dust and other disturbances. Moreover, the click sensitivity (the amount of depression required on the rollerbar so as to provoke a click operation by actuating the mechanical click switch under the counter-action from the resilient counterforce mechanism) is a complex design parameter, since the needs and preferences may vary broadly between users. One user may prefer that a substantial amount of depressive force be applied onto the rollerbar in order to provoke a click operation, whereas another user may prefer only having to use a slight touch. Therefore, prior art pointing devices have used a mechanical click force adjustment arrangement, typically accessible from the underside of the pointing device, where the user may set the threshold force needed for a click operation by turning a dial or displacing a slider handle. Moving the dial or handle affected the bias of the resilient counterforce mechanism and thus the degree to which the user's depression of the rollerbar would be counteracted. However, such a mechanical click force adjustment arrangement, too, was exposed to mechanical wear susceptible of dust and other disturbances, and also had a penalty in component and manufacturing costs.
A mechanical click switch and a resilient counterforce mechanism have other drawbacks as well, which, too, have been identified by the present inventors. For instance, the mechanical resistance needs to be of a certain amount in order to avoid accidental depressions when translating and scrolling the rollerbar. A considerable force is therefore needed to command a click. This may be difficult to perform in a situation where high precision rollerbar movements are frequent, such as for instance in CAD, image processing or designer programs. Also, the actuation of the mechanical switch causes an audible click, which at the same time serves as a click feedback to the user. This audible click is however not customizable. Moreover, the return motion of the resilient counterforce mechanism when the rollerbar depression is released may cause a noticeable effect to the user and disturb the forthcoming rollerbar operation.